The purpose of this study is to explore the role of low-dose immediate-release oral morphine as a novel adjunct pharmacotherapy to enable symptomatic adults with advanced chronic obstructive pulmonary disease (COPD) or interstitial lung disease (ILD) to exercise at higher intensities for longer durations and maximize the psycho-physiological benefits of a supervised exercise training program. We hypothesize that, compared to placebo, exercise training with oral morphine will result in relatively greater improvements in exercise endurance time and intensity ratings of perceived breathlessness during constant-load cardiopulmonary cycle exercise testing (CPET) at 75% of peak power output (PPO).

Supervised exercise training programs (such as pulmonary rehabilitation) are an integral component of the clinical management of COPD or ILD; a proven intervention for improving symptom burden, quality of life, emotional function, exercise capacity, and risk of hospitalization and death. While both low and high intensity exercise training benefits adults with COPD or ILD, evidence supports that higher intensity exercise training produces relatively greater physiological and symptomatic improvements. High intensity exercise of adequate duration is, however, difficult and unpleasant for people with COPD or ILD due to heightened exertional symptoms, particularly breathlessness.These symptoms persist despite the patient's underlying disease being optimally managed according to evidence-based clinical practice guideline standards.

Low-dose immediate-release oral morphine has recently shown promise as a novel adjunct therapy to reduce exertional breathlessness and increase exercise endurance time in people with advanced chronic lung disease (COPD). The purpose of this randomized, double-blind, placebo-controlled, two-arm pilot study is to further explore the role of low-dose immediate-release oral morphine as an adjunct pharmacotherapy to enable symptomatic adults with advanced COPD or ILD to exercise at higher intensities for longer durations and maximize the psycho-physiological benefits of a 5-week supervised exercise training program.

Adults with a clinical diagnosis of COPD or ILD and chronic breathlessness syndrome will be randomized in a 1:1 ratio to exercise training with oral morphine (ExT+MOR) (n=20; 10 COPD and 10 ILD) or exercise training with placebo (diluted simple syrup) (ExT+PLA) (n=20; 10 COPD and 10 ILD). All eligible participants will complete four assessment visits (Visits 1, 2, 3 and 4) and 15 exercise training (T1-15) sessions. Assessment Visits 1 and 3 will include post-bronchodilator (400 mg Salbutamol) pulmonary function testing and a symptom-limited incremental cardiopulmonary exercise test (CPET) to determine peak power output (PPO). Visits 2 and 4 will include a symptom-limited constant-load CPET at 75% of the PPO determined at Visit 1 and a dual energy x-ray absorptiometry (DEXA) scan to assess body composition. Supervised exercise training will be performed three times per week for five weeks on an electronically braked cycle ergometer, supervised by a trained exercise specialist. Exercise sessions will be individualized based on participants' pre-defined PPO (initial intensity of 60% PPO), and progressed to ensure the participant is exercising at an intensity corresponding to a breathlessness intensity rating of between 3-5 Borg 0-10 category ratio scale (CR10) units and can complete at least 20-min of continuous cycling. Exercise duration will be increased in 5-min intervals up to 40-min. Thereafter, exercise intensity will be increased by 5-15% of baseline PPO.

Inclusion Criteria:

• Males and females aged 35 years and over
• Clinical diagnosis of COPD or ILD
• Cigarette smoking history ≥20 years (COPD only)
• Post bronchodilator FEV1 <50% predicted and FEV1/FVC <0.70 (COPD only)
• Chronic breathlessness syndrome (modified Medical Research Council dyspnea score ≥3; Baseline Dyspnea Index focal score ≤6; and/or an Oxygen Cost Diagram rating ≤50% full scale despite optimal treatment of the underlying pathophysiology according to evidence-based clinical practice guidelines
• Report breathlessness as the main limiting factor to incremental CPET
• Body mass index >18.5 kg/m2 and <35 kg/m2

Exclusion Criteria:

• Changed respiratory medication dosage and/or frequency of administration in preceding two weeks
• Disease exacerbation/hospitalization in preceding six weeks
• Arterialized capillary CO2 tension (PacCO2) >50 mmHg at rest
• Self-reported history of drug addiction and/or substance abuse assessed with the CAIG-aid and SISAP questionnaires
• Severe excessive daytime sleepiness assessed with the Epworth Sleepiness Scale (score of 16 out of 24)
• Currently use anti-seizure and/or opioid drug(s)
• Use daytime supplemental oxygen
• Exercise-induced oxyhemoglobin desaturation to <80% on room air
• Participated in a pulmonary rehabilitation program in preceding 6 months
• Allergy/sensitivity to opioid drugs
• Significant extra-pulmonary disease that could impair exercise tolerance
• Contraindication(s) to cardiopulmonary exercise testing (e.g., significant cardiovascular, musculoskeletal, neurological disease)
• Pregnant or currently trying to become pregnant: women of child bearing potential (defined as having a menstrual period within the last 12 months) will be required to take a routine (urine) pregnancy test to rule out the possibility of pregnancy
• Self-report any of the following conditions: anemia or abnormally low blood volume; asthma; hypothyroidism; Addison's disease; renal insufficiency; hypopituitarism; severe malnutrition; digestive disease (any form of colitis disease); prostatic hypertrophy or urethral stricture
• Use of the blood thinning (anti-coagulant) drug Coumadin, Pradaxa, Xarelto and Eliquis in previous 2 weeks

Study medications, both morphine sulphate and placebo, will be dispensed by the research pharmacist according to the patient's randomization assignment. Neither research staff, nor patients, nor the treating physicians will be aware of the treatment assignment before or after randomization.